Fuel injector



J. P. FERR FUEL INJECTOR Nov. 7,1967

2 Sheets-Sheet l Filed March 25, 1964 INVENTOR J/L m5 F? PEER 7 y W J vw M Q y N x VUHMMJTK lvlyl lxUliHLH NN? V? w1 i law. ,IHMIH IIHNQW.. 0 w Q1 mi# am Ml, ill ||||I NF \0 N v N MW Mm W H\ 2, 3 3 7 M 4 .0 2 6 Q1 7 3 3 3 F n w W 3 070 w 3 1 1 United States Patent O 3,351,288 FUEL INJECTOR Julius l. Peri', Columbus, Ind., assignor to Cummins Engine Company, Inc., Columbus, Ind., a corporation of Indiana Filed Mar. 25, 1964, Ser. No. 354,572 18 Claims. (Cl. 239-89) This invention relates generally to fuel injectors for internal combustion engines and more particularly to a fuel injector for a compression ignition engine.

The general object of the invention is to provide a fuel injector having novel means for substantially preventing products of combustion from entering the injector and passing to critical parts thereof or to fuel lines connected to the injector.

Another object is to provide a fuel injector having a novel arrangement for the flow of fuel therethrough.

A further object is to provide an injector construction in which the portions normally subjected to wear and deterioration can be readily replaced without replacement ofthe whole injector.

Still another object is to provide an injector construction having a plunger of the type operated by a rocker arm for injecting the fuel into the cylinder, wherein any side thrust on the plunger from the movement of the rocker arm is reduced.

A still further object is to provide an injector construction provided with passages for the ow of fuel formed by drilling bores in the body of the injector, the construction being such that none of said bores require plugging to close an end of any such bore.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a fragmentary view on a reduced scale of an internal combustion engine having an injector embodying the features of the invention;

FIG. 2 is a longitudinal sectional view through the injector shown in FIG. l;

FIG. 3 is a transverse sectional view taken on the line 3-3 of FIG. 2;

FIG. 4 is a fragmentary sectional view taken on the line 4-4 of FIG. 3;

FIG. 5 is a longitudinal sectional view similar to FIG. 2 but taken in a plane ditfering from that of FIG. 2; and

FIG. 6 is a View similar to FIG. 5 but showing the parts of the injector in a different position, during operation, from the position of the parts shown in FIG. 5.

An injector embodying the features of the invention comprises generally an injector body having a plunger bore and a nozzle at one end of the plunger bore, through which fuel is injected into the cylinder of the engine by a plunger reciprocably mounted in the bore. The body also has a fuel passage comprising a supply portion adapted to be connected at one end to a source of fuel under pressure and at its other end a feed hole connecting the passage with the plunger bore, The feed hole being opened and closed by reciprocation of the plunger. The plunger adjacent one end and the portion of the body surrounding such end portion of the plunger is formed to provide two chambers, one communicating with the nozzle and the other communicating with the feed hole, with a restricted conduit or clearance connecting the two chambers and substantially preventing passage of combustion products from the chamber communicating with the nozzle to the chamber communicating with the feed hole, fuel being forced through said clearance from the last mentioned chamber to the first mentioned chamber during a part of the cycle of operation and tending to ilush out any carbon which may have ICC collected in the clearance. The body also includes a return portion of the passage therethrough, which return portion is adapted to be closed by the plunger when the feed hole is opened thereby.

The body of the injector is formed by a plurality of parts arranged so that those parts subjected to greatest wear may be readily replaced without replacement of the whole injector. Further, such parts are provided with drilled bores constituting the above mentioned supply and return portions. The fact that the body comprises a plurality of parts permits such bores all to be drilled from an outer surface of any such part Without the necessity of plugging any such bore at an end thereof. A part of the return portion is formed merely by pro` viding a clearance between two of the body parts to avoid the necessity of a drilled bore for such part of the return portion.

The plunger for injecting the fuel from the injector into the cylinder is adapted to be actuated on its injection stroke by engine operated means including a rocker arm the movement of which is generally longitudinally of the plunger but has a component laterally of the plunger. Such lateral component would tend to cause unwanted wear on the plunger or in the plunger bore of the body. For this reason, the plunger has a construction which reduces any lateral thrust on the plunger itself so that wear from such lateral thrust is avoided.

In FIG. 1 of the drawings there is shown an injector, indicated generally at 10, mounted in an engine fragmentarily shown. The engine of course may have a plurality of cylinders although one one cylinder is shown. Thus, the engine includes a cylinder head 11, a rock shaft 12 and a rocker arm 13 adapted to be rocked on the rock shaft by the usual engine driven means.

The injector 10, embodying the features of the i11- vention, comprises an elongated injector body indicated generally at 20 and having a plunger bore 21 therethrough, and a nozzle member or cup 22 having nozzle opening 23 therein through which fuel is injected into the cylinder of the engine. A plunger, indicated generally at 26, is reciprocably mounted in the bore 21 for ejecting a quantity of fuel from a chamber in the body 20 upon movement of the plunger 26 toward the nozzle.

The injector body 20, in the present instance, cornprises a generally cylindrical body member or adapter 31, a barrel member 32, and the nozzle member 22 arranged in end-to-end abutting relation. Thus, the abuting end faces, indicated at 33 and 34, of the body and barrel members 31 and 32, respectively, and the abutting end faces, indicated at 36 and 37, of the barrel and nozzle members 31 and 22, respectively, are machined flat to assure surface to surface contact when the parts are engaged.

For holding the parts of the injector body 20 in assembled end-to-end relation, a tubular retainer 40 is provided. The retainer 40 in the present instance is internally threaded as at 41 at one end for engagement with external threads 42 on the end of the body member 31, as viewed in FIGURE 2. The other end of the retainer 40 is provided with an inturned flange 43 defining an internal shoulder 44 for engaging an annular radially outwardly extending flange 47 on the nozzle member 22.

Thus, when the retainer 40 is threaded onto the body member 31, the end faces 33, 34 and 36, 37 of the parts of the injector body 20 are held in abutting engagement.

As heretofore mentioned, the injector body 20` is provided with a bore 21 for receiving the plunger 26. The bore 21, in the present instance, comprises a portion 56 in the body member 31 and a coaxial portion 57 in the 4barrel member 32, the portion 56 being of somewhat larger diameter than the portion 57 so that the upper end of the away from the nozzle'.

plunger 26 does not contact the wall of the bore 56. The interior of the nozzle member 22 constitutes a continuation of the plunger bore 21.

The plunger 26, in the present instance, comprises a fuel injecting and control member 61 and a sleeve 62.

One end, indicated at 63, of the sleeve 62 is secured to the adjacent end of the plunger member 61 by rolling or otherwise forming the end 63 into a circumferential groove 64 formed on lthe end of the plunger portion 61. The outside diameter of the sleeve 62 is somewhat less than that of the portion 56 of the plunger bore so that the sleeve ts loosely within the bore 56 throughout the range of movement of the plunger. A flange 66 is secured to the other end of the sleeve 62 to provide an abutment for one Movement of the plunger 26 toward the nozzle member '22 is effected by the rocker arm 13 acting through an elongated rod-like member or link 72. In the present instance, one end, indicated at 73 (FIG. l), of the link 72 is spherically formed for engaging a complementally shaped seat at one end of the rocker arm 13, and the other end, indicated at 74 (FIG. 2), of the link 72 is spherically formed and engages a complementally shaped seat 76 in the end of the plunger member 61. Such engagement substantially eliminates the imposition of side thrust on the plunger member 61. Such side thrust is further reduced due to the fact that the link 72 is of substantial length so that the angular movement of the link 72 is relatively small.

The reduction of side thrust from the rocking movement of the rocker arm on the plunger member 61 substantially reduces wear between the plunger member 61 and the bore 'portion 57, thereby increasing the service life of the injector.

As heretofore mentioned, the injector body is provided with a fuel passage therethrough, comprising a supply portion and a return portion. One end of the supply portion is adapted to be connected to a fuel supply line, and one end of the return portion is adapted to be connected to a fuel return line. Such fuel supply and return lines, in the present instance, comprise a pair of 'spaced longitudinally extending bores 80 and 81 (FIG.

varying diameters. Theinjector body 20 similarly includes a series of concentric, varying diameter portions adapted to engage the concentric portions of the mounting bore 82 to thus locate the injector in the cylinder head 11. When fully seated in its bore 82, the fuel supply and return .bores 80 and 81 register with circumferential grooves 84 and 85, respectively, in the body member 31. In order to prevent fuel leakage between the fuel supply bore 80 and fuel return bore 81, the body member 31 may include a plurality of longitudinally spaced grooves 86 for receiving O-ring seals 87, there being at least one groove and seal 4on each side of each of the supply and return grooves 84 ,and 85.

The supply portion of the fuel passage, in the present instance, comprises a transverse bore 91 (FIG. 2) extending inwardly from the groove 84, the inner end of which opens into one end of a longitudinal bore 92. The bore 92 extends to the end face 33 of the body member 31, and communicates with one `end (FIGS. 4, 5 and 6) of a longitudinal bore 97 in the barrel member 32, which is laterally offset from the bore 92. The other end of the bore 97 is spaced from the end of the barrel member 32 and is connected to a small transverse bore or feed hole 98 in the barrel member, the inner end of the feed hole 98 opening into the portion 57 of the plunger bore 21. Thus, the supply portion of the fuel passage includes the transverse bore 91, connected but laterally offset longitudinal bores 92 and 97, and the feed hole 98.

According to the present invention, the plunger member 61, as viewed in FIG. 6, and the plunger bore 21, includ lin'g that portion thereof in the interior'of the nozzle member 22, is formed to define two chambers. Thus, the plunger member 61' and the nozzle member 22, when the plunger member is moved away from the nozzle, are shaped to provide a space within the plunger bore cornmunicating with the nozzle openings 23 and the feed hole 98. Such space, in the present instance, comprises an injection chamber 101 defined by the interior of the nozzle member 22 and the end of the plunger member 61, and

another chamber 103 defined by a reduced diameter portion 104 on the plunger member .61 and the adjacent wall of the plunger bore portion 57. The chambers 101` and 103 are connected by a restricted conduit 106 defined between the reducedy diameter portion 104 and the adjacent wall, indicated at 107, of the interior of the nozzle member 22. In the present instance, the reduced diameter portion 104 and wall 107 are cylindrical so that a clearance therebetween provides the restricted conduit 106. The end of the plunger member 61, indicated at 102, is tapered to t a complementally tapered internal surface 108 in the nozzle member 22. The reduced diameter portion 104 also defines a shoulder 111 which is effective to open and close the feed hole 98 upon movements of the plunger 26 in its bore.

According to the present invention, the restricted con-v duit or clearance space 106 is small and preferably about .O03 inch in radial width. Such restricted conduit provides a significant operational advantage in that combustion products, such as carbon particles, which may be forced through the nozzle openings 23 into the chamber 101 are prevented for the most part from entering the chamber 103 and feed hole 98. Thus, carbon particles are deposited upon the adjacent walls of the restricted conduit 106, rather than being carried into the chamber 103 or feed hole 98, or even possibly to the supply and return portions of the fuel passage. The tendency for the carbon particles to accumulate on the walls of the restricted conduit 106 is minimzed -by the high velocity ow of fuel therethrough from the chamber 103 into the injection chamber 101 upon movement of the plunger 26 foward the nozzle. Moreover, even though some carbon may accumulate on the reduced portions 104 and 107, such accumulation does not substantially affect operation of the injector. Further, the prevention of accumulation 0f carbon particles in the area of the feed hole prevents scratching or serration of the plunger member 61 and hence deterioration of the plunger member 61 in the area of the shoulder 111 and the plunger bore in the area of the feed hole 98. Moreover, since the products of combustion are substantially prevented from passing ,through the restricted clearance 106, there is less back flow of such products through the nozzle openings 23.

The lrestricted conduit 106 also provides another advantage where a plurality of injectors are employed, such as in a multi-cylinder engine, wherein the injectors are supplied in common by the supply and return bores and 81 (FIG. l). Thus, because of the fact that, when the .feed hole 98 is uncovered by the shoulder 111, the supply portion of the fuel passage in a particular injector will be in communication with the common supply bore 80, a pressure wave from the cylinder could be transmitted through the supply portion of the fuel passage to the common supply bore and possibly adversely affect the metering of fuel in adjacent injectors. 'Ihe restricted conduit 106 to some extent acts as a barrier to the passage of such pressure wave and thus eliminates this problem.

As a further precaution to the passage of such pressure Waves into the common fuel supply bore 80 valve means in the form of a check valve may be provided in the supply portion of the fuel passage, between the feed hole 98 and fuel inlet groove 84. Such valve means, in the present instance, comprises a ball check valve 114 (FIGS. 3 and 4) mounted in a cavity formed in one of the members comprising the body, in this instance in the body member 31. Such cavity, in the present instance, is formed by a bore 116 extending inwardly from the end face 33 of the body member. A bore 117 coaxial with the bore 116 and of somewhat smaller diameter than the ball 114 extends inwardly from the end face 34 of the barrel member 32 and provides a seat for the ball 114. The inner end of the bore 116 is intersected by a short diagonal bore 118 which opens in the end face 33 in the registry with the longitudinal bore 97. The inner end of the bore 117 is intersected by one end of another diagonal bore 119 in the barrel member 32, which extends to the end face 33 in registry with the longitudinal bore 92. Thus, should the pressure wave, or the affect thereof, pass through the restricted conduit 106 and progress upstream in the supply portion of the fuel passage, such wave would cause the ball 114 to seat and prevent further passage of the wave in the fuel passage.V Such seating of the ball is of course assisted by gravity acting on the ball 114 when in the injector is positioned with its nozzle at the lower end thereof. In some instances, the ball valve 114 may not be necsary because of the prevention of back flow by the restricted clearance 106.

In order to supply a metered quantity of fuel through the feed hole 98 to the injection chamber 101 for injection into the cylinder, flow control means is provided in the supply portion of the fuel passage. Such flow control means in the present instance comprises a plug 121 (FIG. 2) threaded into the outer end of the transverse bore 91. The plug 121 is provided with a metering orifice 123 therethrough for metering fuel into the supply portion of the passage in the injector and through feed hole 98. The plug 121 may be provided with -a socket portion 124 adapted to receive a tool to facilitate installation or removal thereof. A screen 126 may be disposed in the groove 84 to prevent foreign particles from entering the fuel passage.

As heretofore mentioned, the fuel passage also includes a fuel return portion for returning excess amounts of fuel to the fuel return bore 81. Such fuel return portion in the present instance, comprises -a transverse bore 131 (FIGS. 5 and 6) connected at its inner end with the longitudinal bore 97 of the supply portion, preferably coaxial with the feed hole 98. The transverse bore 131 is spaced from the end face 36 of the barrel member 32 so that there is a substantial body of metal radially outside of the metal between the feed hole 98 and the end face 36. Thus, when movement of the plunger 26 toward the nozzle openings 23 builds up a high pressure in the chambers 101 and 103 to effect injection, radially outward expansion of the metal between the feed hole 98 and the end face 36 is substantially prevented because of the backing provided by the metal between the transverse bore 131 and the end face 36 land the fact that the longitudinal bore 97 terminates at a point spaced from the end face 36. The outer end of the of the transverse bore 131 opens into an annular space 132 provided between the barrel member 31 and the tubu lar retainer 40. The annular space 132 thus comprises a part of the return portion of the fuel passage. An annular seal, such as an O-ring 133, may be provided to prevent fuel leakage between the end of the body member 31 and the tubular retainer 40.

The fuel return portion further includes a transverse hole or bore 134 (FIG. 2) in the barrel member 32, the hole 134 extending from the space 132 and intersecting the portion 57 of the plunger bore and being spaced from the transverse bore 131. Thus, the hole 134 has a portion 136 on one side of the bore portion S7 communicating with the annular space 132, and another portion 137 on the opposite side of the portion 57. The portions 136 and 137 of the transverse hole 134 are adapted lto be connected by a circumferential groove 138 formed in the plunger member 61, when the plunger is in its fully advanced position toward the nozzle, as illustrated in FIGS. 2 and 5. The groove 138 thus comprises another part of the return portion of the fuel passage.

A longitudinal bore 141 in the barrel member 32 intersects the portion 137 of the transverse hole 134 and communicates with another longitudinal bore 142 in the body member 31, the bore 142 being connected to the inner end of another transverse bore 143 which opens into the groove 85. Thus, the return portion of the fuel supply passage comprises the transverse bore 131, annular space 132, transverse hole 134, groove 138 in the plunger portion 161, the longitudinal bores 141 and 142, and transverse bore 143.

The groove 138 is so positioned on the plunger member 61 as to close the transverse hole 134, and consequently the return portion of the fuel passage, before the shoulder 111 uncovers the feed hole 98. The return portion of the fuel passage thus permits a circulating ow of fuel through the fuel passage in the injector to purge the passage of air or combustion products so that a solid flow of fuel is applied to the chamber 103 for delivery to the injection chamber 101 upon movement of the plunger 26 toward the nozzle. The provision of the annular space 132, in addition to forming a part of the return portion of the fuel passage, also provides a cooling effect on the parts of the injector adjacent the space 132 because of the aforementioned fuel circulation therethrough.

The foregoing construction provides certain other advantages over other injector constructions from the standpoint of increased service life and economy of manufacture. Thus because of the fact that the injector body 20 is formed by plurality of parts, those parts which are subjected to the greatest wear may be readily replaced without replacement of the entire injector. Thus, the nozzle member 22 and the barrel member 32 may be readily replaced on removal of the retainer 40.

To facilitate proper alignment of the tapered interior 108 of the nozzle member 22 and the tapered end 102 of the plunger member 61, the internal surface portions of the lretainer 40 and the complementary peripheral portions of the nozzle member 22 are dimensioned so that a slight clearance is provided therebetween. Such clearance permits the nozzle member 22 to be shifted with respect to the barrel member 32 to assure accurate alignment of the tapered end 102 and the complementally tapered surface 108. Such alignment is readily achieved by causing the plunger 26 to move to its fully advanced position in the bore 26, as illustrated in FIGS. 2 and 5, and then positioning the nozzle member 22 on the barrel member 32 With the tapered portions properly engaged and subsequently drawing up the tubular retainer 40. Accurate alignment of the barrel member 32 with the body member 31 is assured by the provision of a pair of dowel pins 146 (FIG. 3) only one of which is shown in FIGS. 5 and 6.

The foregoing multiple part construction permits all of the various bores in the injector to be drilled from an outside surface thereby eliminating the necessity of plugging the opposite end of any such bore. The overall cost of the injector is thus reduced and the construction thereof simplified.

I claim:

1. An injector for injecting fuel into a cylinder of an internal combustion engine, comprising an injector body having a plunger bore and a nozzle opening at one end of said plunger bore, said body also having a fuel passage adapted to be connected to a source of fuel under pressure and having a feed hole connecting said passage with said bore, and a plunger reciprocably mounted in said bore for opening and closing said feed hole and movable toward said nozzle opening to eject fuel through said nozzle opening, said plunger being movable away from said nozzle opening to provide space Within said bore communicating with said nozzle opening and said feed hole, said plunger and said bore being formed to provide a restricted conduit therebetween located between said nozzle opening and said feed hole, said space thereby having a portion adjacent said nozzle opening and another portion adjacent said feed hole, said conduit being located between said portions and having a smaller sectional area than either of said portions and thereby substantially preventing passage of combustion products from said one portion to said other portion.

2. The fuel injector according to claim 1, in which said plunger when moved toward said nozzle opening closes said feed hole and forces fuel from said other portion through said restricted conduit to said one portion and also forces fuel through said nozzle opening. v

3. An injector for injecting fuel into a cylinder of an internal combustion engine, comprising an injector body having a plunger bore and a nozzle opening at one end of said plunger bore, said body also having a -fuel passage adapted to be connected to a source of fuel under pressure and having a feed hole connecting said passage with said bore, a plunger reciprocably mounted in said bore for opening and closing said feed hole and movable toward said nozzle opening to eject fuel through said nozzle opening, said plunger and said body being formed to provide an injection chamber between the end of said plunger and said nozzle opening and to provide another chamber around said plunger and communicating with said feed hole when said plunger is moved in one direction, said body and said plunger also being formed to provide a restricted conduit between said plunger and said body connecting said chambers, said conduit substantially preventing passage of combustion products into said other charnber.

4. An injector for injecting fuel into a cylinder of an internal combustion engine, comprising an injector body having a plunger bore and a nozzle opening at one end of said plunger bore, said body also having a fuel passage adapted to be connected to a source of fuel under pressure and having a feed hole connecting said passage with said bore, a plunger reciprocably mounted in said bore for opening and closing said feed hole and movable toward said nozzle opening to eject fuel through said nozzle opening, said plunger and said body being formed to provide an injection chamber between the end of said plunger and said nozzle opening and to provide another chamber around said plunger and communicating with said feed hole when said plunger is moved in one direction, said plunger having a cylindrical portion of reduced diameter adjacent said one end thereof, and said bore having a reduced diameter cylindrical portion cooperating with said reduced diameter portion of said plunger to provide a restricted conduit between said plunger and said body connecting said chambers, said restricted conduit substantially preventing passage of combustion products into said other chamber.

5. A fuel injector according to claim 4, in which said reduced diameter portion of said plunger provides a shoulder on said plunger for opening and closing said feed hole.

6. A fuel injector according to claim 5, in which said injector body includes a barrel member having said plunger bore and said passage extending therethrough and having said feed hole therein, and a cup mounted in end-to-end relation with said barrel member and secured thereto, said cup having said nozzle opening therein and having its interior dimensioned to provide said restricted conduit.

7. A fuel injector according to claim 6. in which said injection chamber is provided in said cup, and said other chamber is provided in said barrel.

8. A fuel injector according to claim 4, in which said reduced diameter portion of said plunger is smaller than the reduced diameter portion of said bore to provide said restricted conduit.

9. A fuel injector according to claim 4, in which said reduced diameter portion of said plunger forms said other chamber with said bore beyond said reduced diameter portion of said bore.

10. An injector for injecting fuel in a cylinder of an internal combustion engine, comprising an injector body having a plunger bore and a nozzle opening at one end of said plunger bore, and a tubular member enclosing a portion of said injector body, said injector body also having a fuel passage including a supply portion having one end adapted to be connected to a fuel supply line and a feed hole at its other end connecting said supply portion with said plunger bore, and a return portion adapted to be connected to a fuel return line, and a plunger reciprocably mounted in said plunger bore for opening and closing said feed hole and movable toward said nozzle opening for ejecting fuel through said nozzle opening, said tubular member being spaced from and defining `a space around said portion of said injector body and said return portion being connected to said other end of said supply portion and including said space.

11. A fuel injector according to claim 10, in which said injector body includes a cylindrical barrel member and a nozzle member, said tubular member comprising a retainer for securing said nozzle member in endtoend relation with said barrel member, said barrel member having said supply portion and said return portion extending therethrough, and a portion of said retainer and said barrel member providing said space therebetween, said space being annular in form and extending for the full length of said barrel member.

12. A fuel injector according to claim 11, in which said annular space communicates with said other end of said supply portion, and said barrel member has a transverse hole communicating with said annular space and forming part of said return portion.

13. A fuel injector according to claim 11, in which said injector body comprises `a body member having threads at one end and said barrel member and said nozzle member, said barrel member being interposed between said body member and said nozzle member, said retainer having internal threads at one end engaging the threads on said body member, and said retainer at its other end having an inturned ange engaging said nozzle member and holding said nozzle member, said barrel member and said body member in end-to-end relation.

14, An injector for injecting fuel into a cylinder of an internal combustion engine, comprising an injector body having a plunger bore and a nozzle opening at one end of said plunger bore, said injector body having a fuel passage including a supply portion having one end adapted to be connected to a fuel supply line and a feed hole at its other end connecting said supply portion with said plunger bore, said passage also including a return portion adapted to be 4connected to a fuel return line and being connected to said other end of said supply portion, and a plunger reciprocably mounted in said plunger bore for opening and closing said feed hole and movable towards said nozzle opening for ejecting fuel through said nozzle opening, said injector body comprising a body member and a barrel 4member secured in end-to-end abutting relation to each,

other, said supply portion having a part in said body member and another part in said barrel member, said parts being laterally offset from each other .and communicating with each other through a cavity formed in one of said members and opening at the abutting surfaces of said members, and valve means mounted in said cavity to close said supply portion when subjected to a pressure wave from sa1d nozzle member.

15. A fuel injector -according to claim 14, in which said cavity is formed in said body member and said barrel member has a hole extending from the abutting surface of said barrel member and forming a valve seat, and said valve means comprises a ball mounted in said cavity and ,adapted to engage said valve seat.

16. An injector for injecting fuel into a cylinder of an internal combustion engine, comprising an injector body having a plunger bore and a nozzle at one end of said plunger bore, said injector body having a fuel passage including a supply portion having one end adapted to be connected to a fuel supply line and a feed hole at its other end connecting said supply portion with said plunger bore, and a return portion adapted to be connected to a fuel return line and being connected to said other end of said supply portion, and a plunger reciprocably mounted in said plunger bore for opening and closing said feed hole and movable towards said nozzle for ejecting fuel through said nozzle, said body comprising a generally cylindrical body member, a barrel member and a nozzle member in end-to-end abutting relation, and a retainer for securing said members in said end-to-end relation, said body member having a pair of bores extending longitudinally from the abutting surface of said body member, said barrel member having a pair of bores extending longitudinally from the abutting surface of said barrel member, one of said body and barrel members having a cavity its abutting surface communicating with one of the bores in said body member and with one of the bores in said barrel member and forming said supply portion therewith, the other of said bores in said body member being aligned with the other of said bores in said barrel member, said barrel member also having a transverse bore extending from the outer peripheral surface thereof to said other bore in said barrel member and another transverse bore extending from the outer peripheral surface of said barrel member into said one bore in said barrel member adjacent said feed hole, said retainer enclosing said barrel member and being radially spaced therefrom to provide a connection between said transverse bores, said transverse bores, said space, and said other bores in said barrel member and said body member constituting said return portion, each of said bores extending from an outer surface of the member in which it is located whereby the use of plugs to close the ends of bores is avoided.

17. An injector for injecting fuel into a cylinder of an internal combustion engine, comprising an injector body having a plunger bore and a nozzle at one end of said plunger bore, said body also having a fuel passage adapted to be connected to a source of fuel under pressure and having a feed hole connecting said passage with saidbore, and a plunger reciprocably mounted in said bore for opening and closing said feed hole and movable toward said nozzle to eject fuel through said nozzle, said plunger bore having a close tit on said plunger for a portion of the length of the plunger bore, a sleeve secured at one end to said plunger and loosely fitting within said plunger bore beyond said close fitting portion and extending beyond said body, spring means coacting with said body and said sleeve for moving said plunger away from said nozzle, and a link loosely extending through said sleeve and having at one end a rocking engagement with said plunger and having its other end adapted to be engaged by a rocker arm for moving said plunger toward said nozzle.

18. A fuel injector according to claim 17, in which said body comprises a body member and a barrel member secured together in end-to-end relation, said plunger bore extending through both of said members and the portion of said plunger bore in said barrel having said close fit on said plunger, the portion of said plunger bore in said body member being enlarged, said sleeve being located in said enlarged portion of said body member and extending beyond the end of said body member and being provided with a flange beyond said end, said plunger bore in said body member being further enlarged at said end to provide a spring receiving cavity, and said spring means comprising a spring mounted in said cavity around said sleeve and engaging said flange for moving said plunger away from said nozzle.

References Cited UNITED STATES PATENTS 1,593,023 7/1926 Knudsen 239-533 1,952,816 3/1934 Mock. 2,727,498 12/ 1955 Reiners 239-90 2,792,259 5/ 1957 Shallenberg 239-90 3,131,866 5/1964 Cummins et al 239-584 3,146,949 9/ 1964 Reiners 239--584 FOREIGN PATENTS 767,717 5 1934 France.

EVERETT W. KIRBY, Primary Examiner. 

1. AN INJECTOR FOR INJECTING FUEL INTO A CYLINDER OF AN INTERNAL COMBUSTION ENGINE, COMPRISING AN INJECTOR BODY HAVING A PLUNGER BORE AND A NOZZLE OPENING AT ONE END OF SAID PLUNGER BORE, SAID BODY ALSO HAVING A FUEL PASSAGE ADAPTED TO BE CONNECTED TO A SOURCE OF FUEL UNDER PRESSURE AND HAVING A FEED HOLE CONNECTING SAID PASSAGE WITH SAID BORE, AND A PLUNGER RECIPROCABLY MOUNTED IN SAID BORE FOR OPENING AND CLOSING SAID FEED HOLE AND MOVABLE TOWARD SAID NOZZLE OPENING TO EJECT FUEL THROUGH SAID NOZZLE OPENING, SAID PLUNGER BEING MOVABLE AWAY FROM SAID NOZZLE OPENING TO PROVIDE SPACE WITHIN SAID BORE COMMUNICATING WITH SAID NOZZLE OPENING AND SAID FEED HOLE, SAID PLUNGER AND SAID BORE BEING FORMED TO PROVIDE A RESTRICTED CONDUIT THEREBETWEEN LOCATED BETWEEN SAID NOZZLE OPENING AND SAID FEED HOLE, SAID SPACE THEREBY HAVING A PORTION ADJACENT SAID NOZZLE OPENING AN ANOTHER PORTION ADJACENT SAID FEED HOLE, SAID CONDUIT BEING LOCATED BETWEEN SAID PORTIONS HAVING A SMALLER SECTIONAL AREA THAN EITHER OF SAID PORTIONS AND THEREBY SUBSTANTIALLY PREVENTING PASSAGE OF COMBUSTION PRODUCTS FROM SAID ONE PORTION OF SAID OTHER PORTION. 